"Turned on full," was the reply.
"Were both the doors of the room locked?"
"Both, yes."
"Any cotton, or cloth, or anything of the sort stuffed in the cracks of the window?"
"No. It's a tight-fitting window, anyway. Are you trying to make a mystery out of this?"
"Cracks in the doors stuffed?" The Thinking Machine went on.
"No." There was a smile about the detective's lips.
The Thinking Machine, on his knees, examined the bottom of one of the doors, that which led into the hall. The lock of this door had been broken when employees burst into the room. Having satisfied himself here and at the bottom of the other door, which connected with the bedroom adjoining, The Thinking Machine again climbed on a chair and examined the doors at the top.
"Both transoms closed, I suppose?" he asked.
"Yes," was the reply. "You can't make anything but suicide out of it," explained the detective. "The Medical Examiner has given that as his opinion-and everything I find indicates it."
"All right," broke in The Thinking Machine abruptly. "Don't let us keep you."
After awhile Detective Mallory went away. Hatch and the scientist went down to the office floor, where they saw the manager. He seemed to be greatly distressed, but was willing to do anything he could in the matter.
"Is your night engineer perfectly trustworthy?" asked The Thinking Machine.
"Perfectly," was the reply. "One of the best and most reliable men I ever met. Alert and wide-awake."
"Can I see him a moment? The night man, I mean?"
"Certainly," was the reply. "He's downstairs. He sleeps there. He's probably up by this time. He sleeps usually till one o'clock in the daytime, being up all night."
"Do you supply gas for your tenants?"
"Both gas and electricity are included in the rent of the suites. Tenants may use one or both."
"And the gas all comes through one meter?"
"Yes, one meter. It's just off the engine room."
"I suppose there's no way of telling just who in the house uses gas?"
"No. Some do and some don't. I don't know."
This was what Hatch had told the scientist. Now together they went to the basement, and there met the night engineer, Charles Burlingame, a tall, powerful, clean-cut man, of alert manner and positive speech. He gazed with a little amusement at the slender, almost childish figure of The Thinking Machine and the grotesquely large head.
"You are in the engine room or near it all night every night?" began The Thinking Machine.
"I haven't missed a night in four years," was the reply.
"Anybody ever come here to see you at night?"
"Never. It's against the rules."
"The manager or a hall boy?"
"Never."
"In the last two months?" The Thinking Machine persisted.
"Not in the last two years," was the positive reply. "I go on duty every night at seven o'clock, and I am on duty until seven in the morning. I don't believe I've seen anybody in the basement here with me between those hours for a year at least."
The Thinking Machine was squinting steadily into the eyes of the engineer, and for a time both were silent. Hatch moved about the scrupulously clean engine room and nodded to the day engineer, who sat leaning back against the wall. Directly in front of him was the steam gauge.
"Have you a fireman?" was The Thinking Machine's next question.
"No. I fire myself," said the night man. "Here's the coal," and he indicated a bin within half a dozen feet of the mouth of the boiler.
"I don't suppose you ever had occasion to handle the gas meter?" insisted The Thinking Machine.
"Never touched it in my life," said the other. "I don't know anything about meters, anyway."
"And you never drop off to sleep at night for a few minutes when you get lonely? Doze, I mean?"
The engineer grinned good-naturedly.
"Never had any desire to, and besides I wouldn't have the chance," he explained. "There's a time check here,"-and he indicated it. "I have to punch that every half hour all night to prove that I have been awake."
"Dear me, dear me," exclaimed The Thinking Machine, irritably. He went over and examined the time check-a revolving paper disk with hours marked on it, made to move by the action of a clock, the face of which showed in the middle.
"Besides there's the steam gauge to watch," went on the engineer. "No engineer would dare go to sleep. There might be an explosion."
"Do you know Mr. Weldon Henley?" suddenly asked The Thinking Machine.
"Who?" asked Burlingame.
"Weldon Henley?"
"No-o," was the slow response. "Never heard of him. Who is he?"
"One of the tenants, on the second floor, I think."
"Lord, I don't know any of the tenants. What about him?"
"When does the inspector come here to read the meter?"
"I never saw him. I presume in daytime, eh Bill?" and he turned to the day engineer.
"Always in the daytime-usually about noon," said Bill from his corner.